1. satellite73

well first we need $$\frac{42}{3}=14$$ to know which term we want

2. satellite73

so it is either the 14th term or the second term depending on how you are counting. makes no difference. the term looks like $\dbinom{16}{2}(x^3)^{14}(-3)^2$

3. satellite73

$\dbinom{16}{2}=\frac{16\times 15}{2}=8\times 15=120$ and $$(-3)^2=9$$ multiply to get your answer

wow my drawing really sucked.... oh well!!

5. mathsux4real

Thanks so much satellite73!